A UN school in Beit Hanoun, Gaza packed with hundreds of refugees from Israel’s military offensive came under fire, killing at least 16 civilians and leaving the now-abandoned building marked with pools of blood, piles of blood-soaked blankets and children clothes, and abandoned toys.

Israel says it is investigating, and suggested a Hamas rocket might have fell to earth far short of its target in Israel, but admitted it can’t discount the Israeli Defense Force (IDF) could have hit the school.  Hamas said Israel alone was responsible and called it an “ugly war crime”.

“Many have been killed, including women and children, as well as UN staff,” said United Nations Secretary General Ban Ki-moon, who was trying to arrange a cease-fire.

While Israelis and Palestinians pointed fingers over which side was responsible, scores of wounded, mostly women and children, were sent streaming into local hospitals.  Those who weren’t hurt were forced to abandon the few belongings they had taken to the shelter and moved on.

The explosions came on the 17th day of an increasingly bloody conflict between Israel and Palestinian militants that has killed nearly 800 people in Gaza, 74 percent of them civilians.  On the Israeli side, 32 soldiers and three civilians have been killed.